Vat dye derived from indirubin and process of making same.



' UNITED STATES rn'r arr pension;

GADIENT ENGI, OF- BASEL, SWITZERLAND, ASSIGNOR TO THE FIRM OF SOCIETY OF GHEMlCA-L- INDUSTRY IN BASLE, OI BASEL, SWITZERLAND.

.VAT"DYE DERIVED FROM INDIRUBIN AND PROCESS OF MAKING SAME.

Specification of Letters Patent.

Patented Jan. '7, 1908.

lipnlieitiou filed March 27.1907 Serial No. 364,910.

T 0 all whom it may COTLCCVIL.

Be it known that l, GADIENT ENGI, doctor of philosophy and chemist, a citizen of the Swiss Republic, and resident of Basel, Switzerland, have invented new and useful Vat Dyestuil's Derived from lindirubin and a yields bytreatment with reducing agents a vat wherein cotton, owing to its comparathey dye valuable violet to heliotrope tintstively sn'iall affinity for the dyestuili", is dyed valueless lilac tints very little fast to washing.

For the same reasons the monobromoindi- I described by Ad. Bacyer (vide Ber-"Lolita der- De'utschen Chemtsclzen Gesellschaft Vol. XIV, page 1745) and obtained by condensing monobromoisatin with indoxyl has no, tinctorial interest. On the contrary I have found that by introducing more than one molecular roportion of a halogen into the molecule ol indirubindriew valuable v at-dycstuffs are obtained, which, as compared with indirubin, have the great advantage that of great intensity and vividiiess, these tints being satisfactorily fast owing to the increased affinity of the dyestuffs for the fiber. The most valuable of the halogens in'this re s' set is bromin;' it may introduced into t e indirubin by treating the latter-with bromin'or substances yielding bromin, best in presence of an'indifi'erent solvent or diluent, preferably nitrobenzene.

The invention is illustrated by the follow- ;ing exam les, the parts being by weight.

Examp e I: 3 parts of indirubin, 30 parts of nitrobenzene and 3.6 parts (about {1 atomic proportions) of bromin are well mixed together and allowed to remam at ordinary temperature for 24 hours; after the lapse of this time, the mixture is heated, if necessary for 3-4:ho'urs, ina reflux apparatus in an oil bath the temperature of which is 13O 14O C. After it has cooled, the mass is filtered, and the solid matter washed with alcohol and dried, whereby the brominated product corresponding probably to a dibromoderivatire of indirubm is obtained :in good yield in the form of a violet crystalline powder. In concentrated sulfuric acid the product is soluble, especially on warming, to a greenish blue solution, from which on addition of water red violet llocks are precipitated. Fun! ing sulfuric acid dissolves the broniinatcd product-with formation of a sulionic acid, the solution being brilliant violet, changing to ref, violet wbci'i the solution is poured into water; in this aqueous solution wool is dyed vivid lilac tints. zenc, the new dycstuli' dissolves somewhat easily even when cold; in the hot solvents the solution is violet red. he cold benzene the dyestull' is hardl soluble, ut in hot benzene it :Iiissclvcs violet solution; in alcohol, even when hot, it is only dillicultly soluble to a red violet solution. By treatment with alkaline reducing agents, the dyestuil' yields a bright yellow vat, wherein cotton without a inordant is dyed intense violet tints satisfactorily fast to washing and to chlorin. I v -i Example ll: A more highly brominated product may be obtained as follows: 3 parts of indirubin, 30 parts of nitrobcnzcne and 5.54.5 parts of bronn'u (6 to 8 atomic proportions) are mixed together and allowed-to In anilin and in nitroben- ..ewhat easily to a reds is,

rernuin for 24 hours, after which time the",

mixture is heated for about 34 hours in a cially when heated, to a green solution from which water precipitates the-dyestuii' in the form of bordcaun red flocks; Filming sill-- furic acid dissolves the dycstuil to a lilac solution, and on addition'ol water and heating a beautiful violet solution is obtained, the sull'onated dyestuil' in which d esiwool vivid lilac tints. In alcohol and cnzcne, even when hot, the new dycstul'l is as good as in soluble. Anilin hardly dissblves, it when cold; when hot it dissolves the dyestuil' easily toe redvioletsoluticn. Coldnitroben 1 1 0 zene dissolves the dyestufi only very sparil'igly, but the hot solvent dissolves it easily to a brilliant violet red solution. When treated with alkaline reducing agents, the dyestufl' yields a bright yellow vat, wherein cotton is dyed violet tints which pass to a Very vivid, advantageously fast heliotrope, when subjected to a short soaping at 90 C.

What I claim is:

1. The herein described process for the manufacture of vat dyestuffs, which consists in treating with a halogen the condensation productcalled indirubin and derived from indoxyl and isatin.

2. As new products, the polyhalogenated vat-dyestuffs obtained by treating lIldllu-I bin with more than two atomic proportions of a halogen, constituting in dry state violet crystalline powders, dissolving in concentrated sulfuric acid with a greenish blue to green coloration, solublein hot anilin and nitrobenzene with a violet coloration and yielding, when treated with alkaline reducing agents, a bright yellow vat dyeing cotton violet tints fast to Washing and chlorin. In Witness whereof I have hereunto signed my name this 11th day of March 1907, in the presence of two subscribing Witnesses. GADIENT ENGI. Witnesses:

GEO. GIFFORD, AMAUD BRAUN. 

